La Lunatica originally worked for the Theatre of Pain, an illegal operation lead by the villainous Brimstone Love where innocents were captured and tortured as entertainment. Her direct superior was Controller 13, who kept Luna under control through a special collar. Luna hunted down individuals the Theatre deemed interesting for their movies and then used her power to trigger traumatic memories in them, which were recorded.
Among their victims were the future version of the X-Men, and when she tried to trigger the traumas of the X-Man Skullfire, she accidentally triggered his powers as well. Skullfire's energy blasted her away and in his rage he destroyed the entire Theatre. Controller 13 tried to escape, but the explosion had destroyed Luna's collar and she turned on him and killed him. Her effect on Skullfire was noticed by his teammates and commented on.
Tim was formerly a reserved member of the team who was hesitant to use his powers and was not confident in his abilities, but after being exposed to her touch, he became mentally imbalanced, even suicidal at times, but on the upside he now had full control over his powers. Some time later, Skullfire noticed Luna walking around and attacked her, wanting to pay her back for the pain she had caused him. She defeated him, but then kissed him. Timothy became romantically involved with Luna and he began to paint his face white (to match hers) and developed a bold demeanor.
Their happiness was short-lived as Brimstone Love tracked down Lunatica and wanted her to return. The X-Men leader Xi'an Chi Xan offered his own services to the Theatre of Pain and left the X-men. Skullfire and Luna returned to the other X-Men 2099 and told them that Xi'an had betrayed them. Skullfire, now appearing more confident and rational, became the new leader and he told the others that Luna was now an X-man as well. There was a lot of animosity and resentment towards Luna because of her past in the Theatre of Pain, but after proving herself she was able to stay on the team.
The X-Men restored Xi'an's sanity and defeated the Theatre of Pain, including Lunatica's sisters. After Victor Von Doom took over the United States, he offered the X-Men Halo City as place where humans and mutants could live in peace. Lunatica and the other X-Men became enforcers of the peace and remained there until the city was destroyed in a flood. During this time Skullfire died, but returned as a being of pure energy. Despite these changes, Luna and Timothy continued to love each other. They, along with some of the other X-Men and heroes of the time, went to the Savage Land, the last habitable place on Earth. Once there, Luna, along with Nostromo, Willow, and several other heroes form part of an expedition team into the jungles to make them inhabitable.
Along the way, they stumbled upon an alien space craft and become trapped inside of it. Willow shapeshifts into one of the previous alien owners of the ship to allow them to escape, but she becomes trapped in that form. With the alien mind taking over, La Lunatica slams her into the water to protect the rest of the group. Nostromo dives in after her and succeeds in subduing her feral persona and returning her to normal but he does not resurface. Luna dives after him, but only finds a strange cocoon at the bottom. Nostromo "hatches" as a full Phalanx form and some of President Doom's operatives arrive to bring the boy to Doom. Some of the operatives turn out to be Phalanx themselves and begin attacking the group. Luna, Willow, and the other heroes fight them off until help arrives.
La Lunatica made recent appearances in the Civil War 2099 arc, working together with her lover Skullfire and Bloodhawk, being knocked down by Shakti Haddad. She also appeared when the teenage time-displaced X-Men traveled to 2099.
In addition to her ability to manipulate emotions, she was able to feed off traumatic (and often repressed memories) emotions to increase her physical abilities to incredible levels, making her extremely strong and superhumanly fast, so much so that she was able to outmaneuver Meanstreak. She also demonstrates a superhuman resistance to injury.